Reliable HSR Communications for Green Smart Cities

Reliable and efficient High speed railways (HSR) is the key component to the concept of Green smart cities to combat with the prevailing traffic congestion on roads and increasing greenhouse gases in the atmosphere. Long Term Evolution - Railways (LTE-R) is an emerging global broadband communication standard that helps in providing intelligent wireless communication services to the passengers and the train operators. The radio frequency power amplifier (RFPA) is a very crucial element in any wireless communication network and is inherently nonlinear. Digital pre-distortion (DPD), the ultimate green communications technique, is used for linearizing RFPA. Moreover, the use of multiple-input-multiple-output (MIMO) technologies achieves the superior data-rates and better transmission reliability requirements of modern and Future (5G and beyond) practical HSR communication systems. The authors study the downlink transmission in a single-user MIMO HSR communications system, where a 10 MHz downlink LTE signal is modulated using the complex mapping scheme 64-QAM. The paper analyzes the effect of DPD with the help of block error rate (BLER) and throughput parameters utilizing different types of MIMO configurations and realizes reliable HSR communications for Green Smart cities. The authors in this paper also evaluate the performance of two important second-order statistical performance indicators, the level crossing rate (LCR) and average fade duration (AFD), for MIMO channels.